<font style="text-shadow: 2px 2px 4px #000000">On Impact Cratering: An introduction</font> Angelo Pio Rossi
Earthgraph GmbH - Bremen (Germany)

Talk I of II

Background: ESA/MEX/HRSC/DLR/FU Berlin

### Role of Impact Cratering * Impact Cratering is largely linked to the birth of Planetary Geology * First case of "interplanetary" uniformitarianism (Moon & Earth) * Ubiquitous process in the Solar System (and anywhere where solid bodies orbit)

### Preliminaries & caveat * Time is limited, pointing to resources * Companion repository at: <a href="https://github.com/aprossi/impact-cratering" target="_blank">https://github.com/aprossi/impact-cratering</a> * Some focus on data (access) * Space bar for navigation advised

### Outline of the 2 talks #### Talk 1 * Impact crater morphology * Impact processes * Crater chronology #### Talk 2 * What we can learn on/from target bodies * Impact cratering in the Solar System

Scale

Source: Kegerreis, et al. (2022)
Video from http://icc.dur.ac.uk/giant_impacts/

Scale

Width: 800 μm / ~Depth: 370 μm Source: From Garvin et al. (2019)

### Craters & structures * **Impact crater:** Pristine rimmed depression formed due to an extraterrestrial/cosmic impact on the surface of a solid body * **Impact structure:** modified (possibly heavily) remnant (morphological, lithological or structural) of an inpact crater _<font size="5">Impact structures are very common among their rare (detected) occurrences on Earth. Less on other Solar System bodies</font>_

Pristine bowl-shaped crater: Tenoumer (Mauritania)

Source: Sentinel/SRTM

Eroded large impact structure: Vredefort (South Africa)

Source: Sentinel/SRTM

Crater morphologies

Source: Redrawn from Kenkmann and Wulff (2018)

Crater morphologies

Multi-ring basins

Source: Redrawn from Rossi and van Gasselt (2018)

Linne crater (the Moon)

Source: NASA/LROC

Copernicus crater (the Moon)

Source: NASA/LROC

### Ejecta <font size="5">Source: NASA/MRO/HiriSE/UoA <a href="https://www.uahirise.org/ESP_034285_1835" target="_blank">ESP_034285_1835</a></font>

(Very!) Distal ejecta

Source: Redrawn from Xu et al. (2023)

Even more distal...

Source: ASI/NASA/APL, from ESA

A very nice thread by P. Metzger on this.

Where are the craters?

Earth

Data from Schmieder and Kring (2020)

Moon

Mars

Phobos

Size: ~ 27 × 22 × 18 km

Source: Threjs JAXA/Japan Planetarium Association.
Shape model from NASA PDS SBN.

Eros

Size: ~ 34 × 11 × 11 km

Source: Threjs JAXA/Japan Planetarium Association.
Shape model from NASA PDS SBN.

Ryugu

Size: ~ 1km × 900 m

Source: Threjs JAXA/Japan Planetarium Association.
Shape model from Watanabe et al. (2019), NASA PDS SBN.

Stages of impact crater formation

Stages: Contact, Compression

Source: French (1998)

Stages: Excavation, Modification

Source: French (1998)

Transitions

Strenght-gravity regime transition

Source: Prieur et al. (2017)

Simple/complex crater transition

Source: Kenkmann (2021)

Simple to complex transition

Source: Pike (1976)

Seee also e.g. Chandnani et al. (2019)

Source: Krüger et al. (2018)

Terrestrial planets: Comparisons

Source: Redrawn from Rossi and van Gasselt (2018)

Simple to complex transition

Source: Redrawn from Kenkmann and Wulff (2018)

Gravities compared

Simple to complex transition

Source: Redrawn from Schenk (2002)

Simple to complex transition

Source: Redrawn from Hiesinger et al. (2016)

Small craters: structure and formation

Source: LPI

Large craters: structure and formation

Source: LPI

Basins: structure and formation

Source: From Miljković et al. (2021)

Basins: structure and formation

Source: From Melosh et al. (2017)

Effect on the rocks: Metamorphism

Source: From French (1998)

Crater chronology

Crater density

Chronology

Source: Neukum (1984)

Source: From French (1998)

Crater production & chronology function

From Xie and Xiao (2023)
See also e.g. Michael (2012) and ref. therein; Robbins et al. (2018).

Crater production on Hadean Earth

Source: From Marchi et al. (2014)

Crater size-frequency analyses

Source: From Arvidson et al. (1979)

Crater size-frequency chronology

Source: Michael (2023)

Source: From French (1998)

Crater size-frequency chronology

Source: Platz et al. (2013)

Mars Sample Return needed...

Source: NASA/JPL-Calteh/ASU/MSSS

See also e.g. McLennan et al. (2012)

Goto Talk 2